The present application is generally related to avoiding aircraft landing short of runways. If aircraft do not approach runways within appropriate ranges of airspeed and rates of descent, the aircraft can land short of the runway.
An air data inertial reference unit (ADIRU) of an aircraft can supply air data (e.g., airspeed, angle of attack, and altitude) and inertial reference information (e.g., position and attitude) to a pilot's electronic flight instrument system displays as well as to other systems on the aircraft. The ADIRU can output a flight path angle (FPA) that can be displayed on both a primary flight display (PFD) and heads-up display (HUD) as a flight path vector (FPV). The FPV can show the aircraft path due to its energy and a pilot can use the FPV to determine the aircraft's flight path.
An aircraft can be landed without the use of a FPV. In such a case, the aircraft can be manually flown to the landing. During manual landing, the pilot maintains airspeed (manually or with autothrottles) and uses either on-board landing guidance (e.g., glideslope indication) or visual guidance from the runway (e.g., visual approach slope indicator (VAST) lights) to indicate whether the aircraft's approach is within an appropriate range, too high, or too low.
A terrain awareness and warning system (TAWS) can be used to prevent accidents where aircraft crash into terrain. Examples of TAWSs are ground proximity warning systems and enhanced ground proximity warning systems. A TAWS can output glideslope alerts and terrain alerts that can be used to alert pilots if they are too far off the path of landing the aircraft on the runway. However, as an aircraft approaches a runway, it is possible not to get any warnings.